1. Field of the Invention
The present invention relates to a locking device and, more particularly, to a door lock for a house.
2. Description of the Related Art
A conventional door lock 10 in accordance with the prior art shown in FIG. 5 comprises a frame 11 mounted in a door 20 and having a through hole 111, a cover plate 16 mounted outside of the door 20, a dead bolt 17 retractably mounted on the frame 11, a support seat 12 mounted in the through hole 111 of the frame 11 and having a mediate portion formed with a recess 121 and a screw bore 122, a locking bolt 123 extended through the frame 11 and screwed into the screw bore 122 of the support seat 12, a driven member 13 rotatably mounted in the recess 121 of the support seat 12 to drive and move the dead bolt 17 so as to lock or unlock the door 20, a rotation knob 14 mounted on a first portion of the support seat 12 and having an end portion secured to a first portion of the driven member 13 to rotate the driven member 13, and a lock core 15 mounted on a second portion of the support seat 12 and secured to a second portion of the driven member 13 to rotate the driven member 13. When in use, the rotation knob 14 drives and rotates the driven member 13 to drive and move the dead bolt 17 so as to lock or unlock the door 20. Alternatively, a key (not shown) is inserted through the through hole 111 of the frame 11 into the key hole 151 of the lock core 15 and is rotated to rotate the driven member 13 to drive and move the dead bolt 17 so as to lock or unlock the door 20.
However, the door lock 10 does not have a dead locking function to lock the door 20 from inside of the door 20, so that a person can use a key or other tool to unlock the lock core 15 to rotate the driven member 13 to drive and move the dead bolt 17 so as unlock the door 20, thereby causing danger to the user inside of the door. In addition, the wall of the recess 121 for mounting the driven member 13 is the weakest portion of the support seat 12, so that a person can break the cover plate 16 to expose the lock core 15 outward from the door 20 and can hit the lock core 15 by a tool to break the wall of the recess 121 of the support seat 12, thereby breaking the door lock 10.